Updating the BIOS on a Matrox Millenium video
card is hampered by the fact that Matrox does not provide instructions
on how to accomplish the flash in a non-FAT-HDD, non-Win environment.
The later versions of UBIOSDOS.exe that Matrox recommends require
a FAT partition to run because of the forced ROM backup procedure.

When progbios.exe runs, it will display the Millenium model
it detects, inform you of the old BIOS version and the new BIOS version,
and ask if you want to proceed. If you answer 'Y', it will erase,
then flash the BIOS using the file you provided.

This is a self-extracting diskette image (built using DSK4PM:
thanks, Daniel Valot). It creates a bootable DOS diskette whose AUTOEXEC.BAT
displays a warning and a menu of options, a menu that looks a lot like
the list of Matrox video cards above! You pick your model of Matrox
Millenium, and run the appropriate batch file.

Gotchas:
Testing with a G400 here, the flash utility would apparently allow
me to flash the G400 using the G450 or G450TV BIOS update file, even though
progbios.exe correctly IDs the G400, so watch out for this one.
It'll also apparently let you try to flash using the TV Output file for
a base series' version. I didn't test this outcome, so if someone
wants to let me know how that combo turns out . . .

Things that might be updated in a future evolution:
Use CHOICE.COM or similar
to eliminate the separate batch files